Zootaxa 1372: 53–68 (2006) ISSN 1175-5326 (print edition) www.mapress.com/zootaxa/ ZOOTAXA 1372 Copyright © 2006 Magnolia Press ISSN 1175-5334 (online edition) Two new species of Isbrueckerichthys Derijst, 1996 (Siluriformes: Loricariidae) from the rio Paranapanema basin, Brazil FERNANDO C. JEREP1, OSCAR A. SHIBATTA1, EDSON H. L. PEREIRA2 & OSVALDO T. OYAKAWA3 1Programa de Pós-Graduação em Ciências Biológicas, Departamento de Biologia Animal e Vegetal, Centro de Ciências Biológicas, Universidade Estadual de Londrina, 86051-990, Londrina, PR. Brazil. E-mail: [email protected] 2Laboratory of Ichthyology, Pontifícia Universidade Católica do Rio Grande do Sul, P.O. Box 1429, 90619- 900, Porto Alegre, RS, Brazil. E-mail: [email protected] 3Museu de Zoologia da Universidade de São Paulo, P.O. Box 42594-970, São Paulo, SP, Brazil. E-mail: [email protected] Abstract Two new Isbrueckerichthys species from Paranapanema river basin are described, I. saxicola and I. calvus, respectively from ribeirão Jacutinga and rio Taquara affluents. Both species present all diagnostic characters of the genus, and differ from their congeners by having bicuspid teeth (vs. simple teeth in I. alipionis), hypertrophied odontodes along the lateral margin of head (vs. hypertrophied odontodes only at the anterior portion of snout in I. epakmos) and longer pectoral-fin spine and shorter caudal peduncle length in relation to I. duseni. The new species can be distinguished from each other by number of odontodes in each minute abdominal platelet (more than six in I. saxicola vs. at most six in I. calvus); by the presence of a plated area under the three first plates of the lateral line in I. saxicola vs. its absence in I. calvus in which this region is naked; by a exposed portion of cleithrum bordering the entire margin of the opercular opening in I. saxicola vs. bordering just the superior portion in I. calvus; and by presenting the exposed surface of supraoccipital plain or slightly convex in I. saxicola vs. strongly convex with an area without odontodes on the center in I. calvus. Keywords: Neotropics, Paranapanema basin, Neoplecostominae. Introduction The genus Isbrueckerichthys was proposed by Derijst (1996) to include the species Pareiorhaphis duseni (Miranda Ribeiro, 1907) and Pareiorhaphis alipionis Gosline, 1947. This proposal was justified based on the discovery of an earlier type-species designation Accepted by M. de Carvalho: 30 Oct. 2006; published: 4 Dec. 2006 53 ZOOTAXA by Regan (1920), which had fixed Hemipsilichthys calmoni Steindachner, 1907 as the type 1372 species of genus Pareiorhaphis, making Pareiorhaphis a synonym of Hemipsilichthys and dislocating P. duseni and P. alipionis, once they do not fit in the new designation (sensu Derijst 1996). Isbrueckerichthys is composed of small- to medium-sized species (up to 90.2 mm SL) of loricariids (suckermouth armored catfishes). Although a phylogenetic diagnosis for Isbrueckerichthys is until now unavailable, this genus is distinguished from other neoplecostomines by a combination of characters: small naked area behind the pterotic- supracleithrum, abdomen with small platelets embedded in skin between pectoral girdle and pelvic-fin insertions, dorsal fin with one spine and seven branched rays, caudal peduncle ovoid in cross-section and lacking a series of papillae on the lower lip of the dentaries. Species of this genus are commonly found in small to medium headwater streams with clear, fast running, and well-oxygenated water, where the bottom is composed of rocks, boulders, and sometimes gravel (Pereira & Reis 2002). The three described species of Isbrueckerichthys are recognized and thought to be endemic to the rio Ribeira de Iguape basin: Isbrueckerichthys duseni (Miranda Ribeiro, 1907) from the upper reaches of that basin in Paraná State, I. alipionis (Gosline, 1947), from the rio Betari, a tributary of rio Ribeira de Iguape and I. epakmos Pereira & Oyakawa, 2003 from a tributary of the rio Juquiá in São Paulo State. In the present paper two new species of Isbrueckerichthys are described, both of them collected in headwater streams of rio Tibagi, rio Paranapanema basin, in Paraná State, Brazil. These species represent the first Isbrueckerichthys species in the Paraná River basin and an increase in the geographic distribution range of the genus. Material and methods Specimens examined belong to the Museu de Zoologia da Universidade Estadual de Londrina, Londrina, State of Paraná (MZUEL), Museu de Zoologia da Universidade de São Paulo, State of São Paulo (MZUSP) and Museu de Ciências e Tecnologia da Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, State of Rio Grande do Sul (MCP). All measurements were taken point to point with digital calipers to the nearest 0.1 mm, under a dissecting microscope when necessary. Measurements and counts of bilaterally symmetrical features were taken from the left side of the body whenever possible; if a feature was missing or broken on the left side, it was examined on the right side. Measurements follow Boeseman (1968), Muller, Mazzoni and Weber (2001), Weber (1985), Bockmann and Ribeiro (2003) and Pereira and Oyakawa (2003). Counts of median plate series were taken according to Schaefer (1997). Additional counts include: plates between dorsal and adipose fins (number of plates in dorsal series between last dorsal-fin branched ray insertion and origin of adipose-fin spine) and plates between adipose and 54 © 2006 Magnolia Press JEREP ET AL. caudal fins (number of plates in dorsal series from just posterior to the adipose-fin ZOOTAXA membrane to the caudal fin). In case of missing teeth, the space left was counted as a 1372 tooth. Standard length is expressed in mm. All other measurements are expressed as percents of standard length, except subunits of the head, which are expressed as percents of head length. Key to the species of Isbrueckerichthys 1 Teeth of dentary and premaxilla without lateral cusp ..................................................... .................................................................... I. alipionis (Ribeira de Iguape River basin) - Teeth of dentary and premaxilla with small lateral cusp............................................... 2 2. Mature males with a clump of hypertrophied odontodes only on anterior portion of snout ........................................................... I. epakmos (Ribeira de Iguape River basin) - Mature males with hypertrophied odontodes along the lateral margin of head ............ 3 3. Short pectoral-fin spine (17.3–21.4 % SL) and long caudal peduncle length (34.6–38.2 % SL) .............................................................I. duseni (Ribeira de Iguape River basin) - Long pectoral-fin spine (21.5–27.4 % SL) and short caudal peduncle length (26.4–30.0 % SL) ......................................................................................................... 4 4. Minute abdominal platelets with much more than six odontodes; plated area under the first three plates of the lateral line; exposed portion of cleithrum bordering all the pos- terior margin of the opercular opening on lateral side of the body; exposed surface of supraoccipital plane or slightly convex...............I. saxicola sp. n. (Paraná River basin) - Minute abdominal platelets with at most six odontodes; nude area under the first three plates of the lateral line; cleithrum not exposed, or when exposed, bordering just the superior portion of posterior margin of the opercular opening on lateral side of the body; exposed surface of supraoccipital strongly convex, with an area without odon- todes at the center...................................................I. calvus sp. n. (Paraná River basin) Isbrueckerichthys saxicola, new species Fig. 1. Holotype. MZUEL 3716; 87.7 mm SL; male; Brazil; Paraná State; Londrina; rio Tibagi basin; ribeirão Jacutinga; 23º14´30”S/51º13´05”W; 18 August 2005; F. C. Jerep, E. S. da Silva, A. Souza. Paratypes. (all from the same locality and collector as the holotype). MZUEL 3717; 3 (3) 59.7–84.7 mm SL; MCP 40209; 2 (2) 59.7-84.7 mm SL; collected with the holotype. MZUEL 3718; 1 (1) 77.8 mm SL; 31 March 2004; H. Mori, F. C. Jerep, E. S. da Silva, A. Souza. MZUSP 90803; 1 (1) 63.6 mm SL; 14 April 2005, F. C. Jerep, E. S. da Silva, A. Souza. TWO NEW ISBRUECKERICHTHYS © 2006 Magnolia Press 55 ZOOTAXA Diagnosis. Isbrueckerichthys saxicola can be distinguished from I. alipionis by having 1372 bifid teeth, with a small lateral cusp (vs. teeth simple, without lateral cusp). Differ from I. epakmos by mature males having margins of head with thin fleshy lobes (vs. soft and rugose fleshy area well developed on anterior portion of snout of mature males) and by the presence of short hypertrophied odontodes along the lateral margin of head (vs. presence of a clump of hypertrophied odontodes located only on anterior portion of snout, directed forward or slightly upwards). Differ from I. duseni by having longer pectoral-fin spine (23.0–27.4 vs. 17.3–21.4 % SL) and shorter caudal peduncle length (27.3–30.0 vs. 34.6–38.2 % SL). Differ from I. calvus by having minute abdominal platelets with frequently about 12 odontodes (vs. minute abdominal platelets with at most six odontodes); plated area under the first three plates of the lateral line (Fig. 3) (vs. naked area under the first three plates of the lateral line); exposed portion of cleithrum bordering the posterior margin of the opercular opening on lateral side of the body (Fig. 3) (vs. cleithrum not exposed, or when exposed, bordering